State whether each of the following is true or false. If false, explain why.
a) Java operators are evaluated from left to right.
b) The following are all valid variable names: _under_bar_, m928134, t5, j7, her_sales$, his_$account_total, a, b$, c, z and z2.
c) A valid Java arithmetic expression with no parentheses is evaluated from left to right.
d) The following are all invalid variable names: 3g, 87, 67h2, h22 and 2h.